The present invention relates a print method of an ink-jet scheme of performing a print operation by discharging an ink and, more particularly, to a print method of performing multi gradation printing which is used to print a medical image.
As a general method of printing a medical image upon digitalization, a method of using a silver salt printer for outputting an image obtained by exposing a silver salt film with a laser is known.
In the silver salt scheme, wet type printers are often used. Demands, however, have arisen for the development of dry type printers in consideration of liquid waste disposal, cost, and the like. As such printers, printers using the ink-jet print method, e.g., a bubble-jet printer designed to discharge an ink by exerting energy thereon, have been developed.
In this method, two or more types of ink dots having different densities are formed to be stacked on each other in units of pixels to perform a print operation, thereby forming a multi gradation image. For an ink used in an ink-jet printer, a dye or pigment is used as a coloring material. A dye is mainly used in consideration of solubility with respect to water, safety, stability, and the like.
Considering safety in terms of mutagenicity, acute toxicity, and the like, the types of coloring materials (dyes and pigments) which can be used are limited. Of coloring materials, a dye is an organic material, in which Cxe2x80x94C double-bonds and Nxe2x80x94N double bonds exist in the molecules. For this reason, this material is subjected to deterioration by oxidation, deterioration by UV, and the like. If this ink is exposed to sunlight by accident or left on a desk for a long period of time, the image undergoes color deterioration or color change. As a result, the image cannot be used for a medical examination.
To obtain a stable image, therefore, the image is generally protected by mixing an antioxidant or UV light absorber into an ink or image receiving paper or laminating the image.
It is, however, difficult to completely prevent a change in quality of a dye even by this method. In addition, lamination leads to an increase in cost and requires considerable heat energy.
The present invention has been made to solve the above problems and, has as its object to provide an ink-jet print method of printing a medical image, in which pieces of information such as a gray scale and the like are printed in a predetermined place other than the effective area of an image with an image preservation determination ink.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.